油-纸绝缘内部空间电荷的运动规律
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摘要
针对换流变压器油–纸绝缘内部合成电场的计算,目前尚无有效的方法考虑空间电荷对合成电场的附加影响,致使内绝缘设计误差较大。为此对现有的上流有限元法进行改进,添加时间步长,基于迭代思想,提出瞬态上流元法,在考虑空间电荷运动的情况下,计算油–纸绝缘内部合成电场。单层油纸绝缘实验结果与仿真结果的对比验证了该方法的正确性。研究了不同电场强度下,油–纸绝缘介质内部空间电荷的运动规律和合成电场的畸变情况,并利用该方法进一步研究了双层油–纸绝缘系统内部空间电荷的分布规律。研究结果表明:瞬态上流元法具有较高的精确度;在载流子迁移率一定的情况下,初始电场强度越大,电荷运动到动态稳定所需时间越短,且内部合成电场畸变率越大;双层油–纸交界面对空间电荷具有阻碍效应,可通过设置适当的界面势垒模拟这一特性。该方法的提出为提高特高压直流设备的内绝缘优化设计水平提供了理论与技术支撑。
No effective method can be adopted to consider the influence of space charges when calculating the total electric field distribution in the main insulation system of the valve-side winding of converter transformer. In order to calculate total electric field in oil-paper insulation system, we put forward a new simulation method in oil-paper insulation based on a transient upstream finite element method(TUFEM), in which the time variable is considered. The TUFEM is used to calculate the total electric field in oil-paper insulation system by considering motion law of space charges. The simulation method is verified by comparing the simulation results to the test data in references. The motion law of space charges and distribution characteristics of the electric field under difference voltage values in single-layer oil-paper insulation is obtained. The distribution of space charge in a double-layer oil paper insulation system is further studied by this method. The results show that the TUFEM has an excellent accuracy compared with test data in references. When carrier mobility is a constant, the higher the initial electric field intensity is, the less time the space charge reaching dynamic stability will take, and the greater distortion rate of internal total electric field will be. Space charges are hindered on the interface of double layers of oil-paper insulation, which can be simulated by setting an appropriate interface potential barrier.This method will promote the design and optimization level of UHVDC converter transformers.
No effective method can be adopted to consider the influence of space charges when calculating the total electric field distribution in the main insulation system of the valve-side winding of converter transformer. In order to calculate total electric field in oil-paper insulation system, we put forward a new simulation method in oil-paper insulation based on a transient upstream finite element method(TUFEM), in which the time variable is considered. The TUFEM is used to calculate the total electric field in oil-paper insulation system by considering motion law of space charges. The simulation method is verified by comparing the simulation results to the test data in references. The motion law of space charges and distribution characteristics of the electric field under difference voltage values in single-layer oil-paper insulation is obtained. The distribution of space charge in a double-layer oil paper insulation system is further studied by this method. The results show that the TUFEM has an excellent accuracy compared with test data in references. When carrier mobility is a constant, the higher the initial electric field intensity is, the less time the space charge reaching dynamic stability will take, and the greater distortion rate of internal total electric field will be. Space charges are hindered on the interface of double layers of oil-paper insulation, which can be simulated by setting an appropriate interface potential barrier.This method will promote the design and optimization level of UHVDC converter transformers.
引文
[1]陈义龙,齐波,李成榕.极性反转条件下的油纸沿面绝缘界面电荷特性[J].高电压技术,2017,43(6):1965-1972.CHEN Yilong,QI Bo,LI Chengrong.Characteristics of interface charge on oil-paper surface insulation under polarity reversal voltage[J].High Voltage Engineering,2017,43(6):1965-1972.
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[5]周远翔,戴超,黄猛,等.电老化过程中直流电场对油纸绝缘空间电荷特性的影响[J].高电压技术,2016,42(12):3861-3867.ZHOU Yuanxiang,DAI Chao,HUANG Meng,et al.Effect of DC electric field on space charge characteristics of oil-paper insulation in electrical aging process[J].High Voltage Engineering,2016,42(12):3861-3867.
[6]唐超.油–纸绝缘介质的直流空间电荷特性研究[D].重庆:重庆大学,2010:17-74.TANG Chao.Studies on the DC space charge characteristics of oil-paper insulation materials[D].Chongqing,China:Chongqing Uni-versity,2010:17-74.
[7]林久胜.换流变压器端部电场计算与分析[D].沈阳:沈阳工业大学,2015.LIN Jiusheng.Calculation and analysis of converter transformer end electric field[D].Shenyang,China:Shenyang University of Technology,2015.
[8]刘刚,李琳,赵小军,等.油–纸绝缘结构非线性交直流复合电场计算的定点频域有限元法[J].中国电机工程学报,2012,32(1):154-161.LIU Gang,LI Lin,ZHAO Xiaojun,et al.Analysis of nonlinear electric field of oil-paper insulation under AC-DC hybrid voltage byfixed point method combined with FEM in frequency domain[J].Proceedings of the CESS,2012,32(1):154-161.
[9]ALISON J M,HILL R M.A model for bipolar charge transport,trapping and recombination in degassed crosslinked polyethene[J].Journal of Physics D:Applied Physics,1994,27(6):1291-1299.
[10]ROY S L,TEYSSEDRE G,LAURENT C,et al.Description of charge transport in polyethylene using a fluid model with a constant mobility:Fitting model and experiments[J].Journal of Physics D:Applied Physics,2006,39(7):1427-1436.
[11]TIAN J,ZHOU Y,WANG Y.Simulation of space charge dynamics in low-density polyethylene under external electric field and injection barrier heights using discontinuous galerkin method[J].IEEE Transactions on Dielectrics and Electrical Insulation,2011,18(5):1374-1382.
[12]TAKUMA T,IKEDA T,KAWAMOTO T.Calculation of ion flow fields of HVDC transmission lines by the finite element method[J].IEEE Transactions on Power Apparatus and Systems,1981,100(12):4802-4810.
[13]JIN S,RUAN J G,DU Z Y,et al.Simulation of charge transport in oil-paper insulation using transient upstream FEM[J].CSEE Journal of Power and Energy System,2015,1(3):3-8.
[14]JIN S,RUAN J G,DU Z Y,et al.Charge transport simulation in single-layer oil-paper insulation[J].IEEE Transactions on Magnetics,2016,52(3):1-4.
[15]雷清泉,李盛涛.关于工程电介质中几个经常涉及的问题与思考[J].高电压技术,2015,41(8):2473-2480.LEI Qingquan,LI Shengtao.Several important issues and thinking about engineering dielectrics[J].High Voltage Engineering,2015,41(8):2473-2480.
[16]廖瑞金,郝建,杨丽君,等.变压器油纸绝缘频域介电特征量与绝缘老化状态的关系[J].电工技术学报,2012,27(5):43-49,76.LIAO Ruijin,HAO Jian,YANG Lijun,et al.Relationship between frequency domain dielectric characteristic quantity and aging status of transformer oil-paper insulation[J].Transactions of China Electrotech nical Society,2012,27(5):43-49,76.
[17]ZHU Q.Space charge distribution in oil impregnated papers under temperature gradient[J].IEEE Transactions on Dielectrics and Electrical Insulation,2015,22(1):142-151.
[18]周远翔,黄猛,陈维江,等.直流电场下油纸绝缘介质界面处的空间电荷特性[J].高电压技术,2011,37(10):2417-2423.ZHOU Yuanxiang,HUANG Meng,CHEN Weijiang,et al.Space charge characteristics of the interface in oil-paper insulation under DC voltage[J].High Voltage Engineering,2011,37(10):2417-2423.
[19]LE ROY S,SEGUR P,TEYSSEDRE G,et al.Description ofbipolar charge transport in polyethylene using a fluid model with aconstant mobility:model prediction[J].Journal of Physics D:Applied Physics,2004,37(2):298-305.
[20]朱庆东,吴锴,朱文兵,等.温度梯度下油纸绝缘空间电荷特性的数值仿真[J].高电压技术,2016,42(3):923-930.ZHU Qingdong,WU Kai,ZHU Wenbing,et al.Numerical simulation of space charge property in oil-paper insulation space under temperature gradient[J].High Voltage Engineering,2016,42(3):923-930.
[21]WU K,ZHU Q,TU Y,et al.Simulation study on the effect of interface charge between oil and paper[C]∥International Symposium on Electrical Insulating Materials.[S.l.]:IEEE,2014:366-369.
[2]彦超,周远翔,聂德鑫,等.直流电压作用下油纸绝缘局部放电发展不同阶段的理化特性[J].高电压技术,2014,40(1):80-86.SHA Yanchao,ZHOU Yuanxiang,NIE Dexin,et al.Partial discharge process in transformer oil and electrical insulation paper under DC stress[J].High Voltage Engineering,2014,40(1):80-86.
[3]MORSHUIS P,JEROENSE M.Space charge in HVDC cable insulation[C]∥1997 IEEE Conference on Electrical Insulation and Dielectric Phenomena.Minneapolis,USA:IEEE,1997:28-31.
[4]郝建,黄博,CHEN G,等.空间电荷在多层结构油纸绝缘混合体系的积聚规律及其对电场分布的影响[J].高电压技术,2017,43(6):1973-1979.HAO Jian,HUANG Bo,CHEN G,et al.Space charge accumulation behavior of multilayer structure oil-paper insulation and its effect on electric field distribution[J].High Voltage Engineering,2017,43(6):1973-1979.
[5]周远翔,戴超,黄猛,等.电老化过程中直流电场对油纸绝缘空间电荷特性的影响[J].高电压技术,2016,42(12):3861-3867.ZHOU Yuanxiang,DAI Chao,HUANG Meng,et al.Effect of DC electric field on space charge characteristics of oil-paper insulation in electrical aging process[J].High Voltage Engineering,2016,42(12):3861-3867.
[6]唐超.油–纸绝缘介质的直流空间电荷特性研究[D].重庆:重庆大学,2010:17-74.TANG Chao.Studies on the DC space charge characteristics of oil-paper insulation materials[D].Chongqing,China:Chongqing Uni-versity,2010:17-74.
[7]林久胜.换流变压器端部电场计算与分析[D].沈阳:沈阳工业大学,2015.LIN Jiusheng.Calculation and analysis of converter transformer end electric field[D].Shenyang,China:Shenyang University of Technology,2015.
[8]刘刚,李琳,赵小军,等.油–纸绝缘结构非线性交直流复合电场计算的定点频域有限元法[J].中国电机工程学报,2012,32(1):154-161.LIU Gang,LI Lin,ZHAO Xiaojun,et al.Analysis of nonlinear electric field of oil-paper insulation under AC-DC hybrid voltage byfixed point method combined with FEM in frequency domain[J].Proceedings of the CESS,2012,32(1):154-161.
[9]ALISON J M,HILL R M.A model for bipolar charge transport,trapping and recombination in degassed crosslinked polyethene[J].Journal of Physics D:Applied Physics,1994,27(6):1291-1299.
[10]ROY S L,TEYSSEDRE G,LAURENT C,et al.Description of charge transport in polyethylene using a fluid model with a constant mobility:Fitting model and experiments[J].Journal of Physics D:Applied Physics,2006,39(7):1427-1436.
[11]TIAN J,ZHOU Y,WANG Y.Simulation of space charge dynamics in low-density polyethylene under external electric field and injection barrier heights using discontinuous galerkin method[J].IEEE Transactions on Dielectrics and Electrical Insulation,2011,18(5):1374-1382.
[12]TAKUMA T,IKEDA T,KAWAMOTO T.Calculation of ion flow fields of HVDC transmission lines by the finite element method[J].IEEE Transactions on Power Apparatus and Systems,1981,100(12):4802-4810.
[13]JIN S,RUAN J G,DU Z Y,et al.Simulation of charge transport in oil-paper insulation using transient upstream FEM[J].CSEE Journal of Power and Energy System,2015,1(3):3-8.
[14]JIN S,RUAN J G,DU Z Y,et al.Charge transport simulation in single-layer oil-paper insulation[J].IEEE Transactions on Magnetics,2016,52(3):1-4.
[15]雷清泉,李盛涛.关于工程电介质中几个经常涉及的问题与思考[J].高电压技术,2015,41(8):2473-2480.LEI Qingquan,LI Shengtao.Several important issues and thinking about engineering dielectrics[J].High Voltage Engineering,2015,41(8):2473-2480.
[16]廖瑞金,郝建,杨丽君,等.变压器油纸绝缘频域介电特征量与绝缘老化状态的关系[J].电工技术学报,2012,27(5):43-49,76.LIAO Ruijin,HAO Jian,YANG Lijun,et al.Relationship between frequency domain dielectric characteristic quantity and aging status of transformer oil-paper insulation[J].Transactions of China Electrotech nical Society,2012,27(5):43-49,76.
[17]ZHU Q.Space charge distribution in oil impregnated papers under temperature gradient[J].IEEE Transactions on Dielectrics and Electrical Insulation,2015,22(1):142-151.
[18]周远翔,黄猛,陈维江,等.直流电场下油纸绝缘介质界面处的空间电荷特性[J].高电压技术,2011,37(10):2417-2423.ZHOU Yuanxiang,HUANG Meng,CHEN Weijiang,et al.Space charge characteristics of the interface in oil-paper insulation under DC voltage[J].High Voltage Engineering,2011,37(10):2417-2423.
[19]LE ROY S,SEGUR P,TEYSSEDRE G,et al.Description ofbipolar charge transport in polyethylene using a fluid model with aconstant mobility:model prediction[J].Journal of Physics D:Applied Physics,2004,37(2):298-305.
[20]朱庆东,吴锴,朱文兵,等.温度梯度下油纸绝缘空间电荷特性的数值仿真[J].高电压技术,2016,42(3):923-930.ZHU Qingdong,WU Kai,ZHU Wenbing,et al.Numerical simulation of space charge property in oil-paper insulation space under temperature gradient[J].High Voltage Engineering,2016,42(3):923-930.
[21]WU K,ZHU Q,TU Y,et al.Simulation study on the effect of interface charge between oil and paper[C]∥International Symposium on Electrical Insulating Materials.[S.l.]:IEEE,2014:366-369.